Close your eyes, because the computer needs to perform magic at this point;

Open your eyes and behold: the tab will be closed (or a message will be prompted asking you to save your works).

Alternatively you could build a small shrine to worship the God of SublimeText and pray for the tab to be closed. This method has proven to be quirky at best and can cause spontaneous combustion of various body parts, usually depending on whether or not you registered ST2.